Audio mixer



FIG. 1 is a perspective view of the top, front and left side of an audio mixer showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The portions of the audio mixer visible through the vent openings are shown in broken lines and therefore form no part of the claimed design. 

The ornamental design for an audio mixer, as shown and described. 